CONTENTS OF VOL. XXI. V 



Page 

 Mr. T. S. Davies on the Employment of Polar Coordinates in 



expressing the Equation of the Straight Line, and its appli- 

 cation to the proof of a property of the Parabola 190 



Mr. R. Warington on the Change of Colour in the Biniodide 



of Mercury 192 



Mr. H. Croft on a new Oxalate of Chromium and Potash .... 197 

 Mr. R. "Warington's additional Observations on the Red Oxalate 



of Chromium and Potash 201 



The Rev. P. Kelland's Reply to some Objections against the 



Theory of Molecular Action according to Newton's Law . . 202 

 Sir D. Brewster on the Connexion between the Phenomena of 



the Absorption of Light and the Colours of thin Plates .... 208 

 Mr. Earnshaw on the Theory of the Dispersion of Light ; in 



reply to Prof. Powell's Note 217 



Mr. H. A. Goodwin's Proof of Professor Wallace's Property of 



the Parabola 219 



Proceedings of the Royal Society 220 



Royal Irish Academy 228 



On Curcumine, by M. Vogel, jun 233 



On the Action of Acids on Curcumine, by M. Vogel, jun 234 



On the Action of Alkaline Substances on Curcumine 235 



Insoluble Salts of the Alkaline Earths dissolved by Hydrochlo- 



rate of Ammonia and Chloride of Sodium 236 



Production of Formic Acid in Oil of Turpentine 236 



Precipitation of certain Salts by excess of Acids, by M. Wacken- 



roder 236 



Solubility of Salts in Pernitrate of Mercury 237 



On Laurostearine, by M. Marsson 237 



On Laurostearic Acid, by M. Marsson 238 



On the Presence of Antimony in Arsenious Acid 238 



Discovery of a new Metal, Didym 239 



Meteorological Observations for July 1842 239 



Table 240 



NUMBER CXXXVII I. —OCTOBER. 



Mr. Gulliver's Contributions to the Minute Anatomy of Ani- 

 mals. No. IV 241 



M. Dufrenoy's Description of Greenovite. 246 



Mr. Smee's New Definition of the Voltaic Circuit, with 

 Formulae for ascertaining its Power 248 



The Rev. P. Kelland's Reply to some Objections against the 

 Theory of Molecular Action according to Newton's Law. . . . 263 



Mr. W. H. Balmain's Observations on the Formation of Com- 

 pounds of Boron and Silicon with Nitrogen and certain Metals 270 



Prof. Miller on the Optical Constants of Tourmaline, Dioptase 

 and Anatase 277 



